Devils River Minnow Plan Will Protect Water Resources

DEL RIO, Texas — Working to keep plenty of clean water flowing in Southwest Texas rivers, streams and springs will benefit people as well as a rare fish. This is according to a scientist who worked on the recovery plan for the Devils River minnow (Dionda diaboli), a plan recently approved by the U. S. Fish and Wildlife Service and Texas Parks and Wildlife Department.

The species was listed as threatened in 1999 under the federal Endangered Species Act and is also listed as threatened by the State of Texas.

This small fish is currently known to occur in three streams in Val Verde and Kinney counties, all tributaries to the Rio Grande: Devils River, San Felipe Creek and Pinto Creek. The current status of the species in Sycamore Creek, and in the Rio Salado drainage in Chihuahua, Mexico is not known. The species was once found in the lower portions of the Devils River (now Amistad Reservoir in Val Verde County), Las Moras Creek (Brackettville in Kinney County), and from the Rio San Carlos (Mexico) but is no longer believed to be there.

“This is one of the premier examples of an indicator species,” said Gary Garrett, Ph.D., a Texas Parks and Wildlife Department inland fisheries scientist who has been researching and implementing fish conservation efforts in West Texas for decades. “As we’ve shown in our studies in artificial steams, as well as what we’ve found in nature, this minnow does well and it’s a hardy survivor when stream habitat quality is good, but it really suffers when the habitat declines. This fish needs clean flowing water, and that’s good for the people of Kinney and Val Verde counties as well.”

The Devils River minnow depends on the constant clean flow of spring waters and is at extreme risk from habitat loss and degradation caused by spring flow declines, water pollution and impacts from introduced, non-native species.

The recovery plan identifies specific, voluntary actions that will help recover the fish so it may eventually be removed from the list of threatened and endangered species.

Proposed recovery actions include: (1) maintain and enhance Devils River minnow populations and habitats range-wide; (2) control the invasion of non-native species; (3) establish additional Devils River minnow populations within the historic range and (4) maintain genetic reserves of Devils River minnow through captive propagation until no longer needed.

Work on several of these steps has already begun.

“We have just completed a five-year, detailed study on Devils River minnow populations in the river, with the support and coordination of private landowners and the Nature Conservancy of Texas,” Garrett said. “Two landowners allowed us access and let us stay on their property to study the fish. And there is an ongoing study of the minnow in Pinto Creek in Kinney County north of Brackettville.”

Regarding enhancing minnow populations and habitat and controlling invasive exotic species, Garrett said management plans developed by the City of Del Rio and the San Felipe Country Club with TPWD help are aiding that cause.

“There are a series of things they’re doing along San Felipe Creek in Del Rio,” Garrett said, “including reducing pollution and enhancing streamside habitat. In some areas they have just stopped mowing along the creek and the native plants that are better for native species then come back. Sylvestre Sorola, TPWD wildlife biologist in Del Rio, is helping to coordinate removal of some non-native exotic plants along the creek, including giant river cane, and that’s an ongoing project.

“We do have introduced armored catfish in San Felipe Creek that eat the same food as the minnow — we’re still considering how to approach that problem,” Garrett said. He also said the federal fish hatchery in San Marcos is maintaining a captive breeding population of several hundred minnows, providing a repository to restock the fish if needed, although right now “if we wanted to restock we would just go to nature because the wild populations are doing pretty well.”

TPWD has also just concluded a multi-year study at Heart of the Hills Fisheries Science Center on competition and interaction between this fish and other fish it lives with.

The recovery plan underwent a public review period earlier in 2005 and was peer-reviewed by five outside experts to ensure the plan was based on the best available scientific information.

Regarding the recovery plan, one private landowner commented that recent improvement in the status of the fish in the Devils River is “proof that cooperation between U.S. Fish and Wildlife Service, Texas Parks and Wildlife and landowners can work to accomplish goals.”

The USFWS uses a priority system for recovery of listed species with a range of one to 18, with one ranking as the highest. The Devils River minnow has a recovery priority of two, which indicates that Devils River minnow is a species with a high degree of threat yet has high recovery potential.

Copies of the recovery plan can be downloaded from online or requested from the U.S. Fish and Wildlife Service, Austin Ecological Services Field Office, 10711 Burnet Road, Suite 200, Austin, Texas, 78758.